Re: sched: Improve load balancing in the presence of idle CPUs

From: Jason Low
Date: Tue Apr 07 2015 - 19:28:36 EST

On Sat, 2015-04-04 at 15:29 +0530, Preeti U Murthy wrote:

> Solution 1: As exists in the mainline
> Solution 2: nohz_idle_balance(); rebalance_domains() on the ILB CPU
> Solution 3: Above patch.
> I observe that Solution 3 is not as aggressive in spreading load as
> Solution 2. With Solution 2, the load gets spread within the first 3-4
> seconds,

hmm, so 3-4 seconds still sounds like a long time.

> while with Solution3, the load gets spread within the first 6-7
> seconds. I think this is because, the above patch decides to further
> nohz_idle_load_balance() based on the load on the current ILB CPU which
> has most likely pulled just one task.

Okay, so perhaps we can also try continuing nohz load balancing if we
find that there are overloaded CPUs in the system.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at